Parachute

ABSTRACT

Stress-tailored bodies for aerial decelerator devices, such as cross parachutes, comprising at least a pair of flexible segments secured together to form the decelerator structure. The segments forming the decelerator structure are formed of either a nonporous film or a woven nylon fabric of the type normally employed for parachute structures. Reinforcing scrim or lines are secured to the surface of the segments with certain of the scrim axes being generally oblique to the axis of the particular segment, and in addition, load lines or additional reinforcement is applied having an axis generally parallel to the axis of the particular segment at the point where it is applied. Load or shroud lines are also provided which extend along the edges of the individual segments, with the free ends of these load lines being secured to a common load ring or member.

a i i 1 Y I Unite tates aet 11 3,602,462

[72] lnventors Richard J. Slater; 3,127,137 3/1964 Downing 244/145 LelanR. Jamison, Jr., both of Northfield, 3,331,573 7/1967 Winker et al.244/145 Minn.

Primary ExammerM1lton Buchler [21] P sll'sgl Assistant ExaminerCarl A.Rutledge [22] Ffled 1969 AttorneyOrrin M Haugen [45] Patented Aug. 31,1971 [73] Assignee G. T. Schieldahl Company Normfield Minn ABSTRACT:Stress-tailored bodies for aerial decelerator devices, such as crossparachutes, comprising at least a pair of [54] PARACHUTE flexiblesegments secured together to form the decelerator 4 Claims, 3 DrawingFigs. structure. The segments forming the decelerator structure are vformed of either a nonporous film or a woven nylon fabric of [52] U.S.Cl244/145 the type normally employed for parachute Structures m 17/02forcing scrim or lines are secured to the surface of the seg- 1 Field MSearch 244/142 ments with certain of the scrim axes'being generallyoblique to 145 the axis of the particular segment, and in addition, loadlines or additional reinforcement is applied having an axis generally[56] References cued parallel to the axis of the particular segment atthe point where UNITED STATES PATENTS it is applied. Load or shroudlines are also provided which ex- 2,412,392 12/1946 Finken 244/145 tendalong the edges of the individual segments, with the free 2,745,6155/1956 Fogal 244/145 ends of these load lines being secured to a commonload ring 3,104,856 9/1963 Knacke et a1. 244/145 or member.

I/VIYI, /2 I PARACHUTE The present invention relates generally to animprovement in parachute -or other types of aerial deceleratorstructures, and more specifically to this type of structure whichcomprises a pair of generally rectangular flexible segments securedtogether in common crossover zone relationship. In addition to theflexible segments, the cross parachute structure may also include meshgores secured to lateral edges of the individual rectangular segments soas to form a substantially circular structure. The structure of thepresent invention provides a shaped structure which is light in weight,has few seams, and which has extremely stable flightor decelerationcharacteristics and good shock resistance.

In the design and manufacture of aerial decelerator structures, it isgenerally necessary to provide for controlled passage of air through thestructure, for example the parachute canopy, or through portionsthereof, in order to achieve aerodynamic stability. This control indecelerator devices is ordinarily accomplished by using a structurefabricated from air permeable material, or by utilizing cohesivenonporous or nonpermeable films having openings or pores therein toachieve air permeability. With the advent of nonporous materialincluding plastic films and the like, which films have the strength forwithstanding the rigors of operation as a parachute canopy, variousweight, strength and cost advantages can be gained by the utilization ofthis material. An example of material which is commercially availableand which has sufficient strength to be employed in aerial deceleratoroperations is stress-oriented polyethylene terephthalate, this materialbeing available from E. I. DuPont deNemours Corp. of Wilmington,Delaware, under the code name of Mylar." In the structure of the presentinvention, this film material is reinforced with a suitable scrim orwebbing, the scrim or webbing providing the resistance to tear which isordinarily deemed desirable.

The nonporous films are generally available in a variety of filmthicknesses, widths and lengths, this availability being limited to flatsheets of material for economic reasons. Parachute structures inaccordance with the present invention can conveniently be fabricatedfrom flat material, the canopy conforming to the desired configurationupon exposure to a dynamic air stream during use as a decelerator. Thecanopy is formed so as to achieve optimum drag, stability and strengthalong with a minimum of area, and a minimum of weight.

Specifically, and in one aspect of the present invention, the parachutecanopy or structure consists of a pair of generally rectangular flexiblesegments, each segment having an elongated axis, the segments beingcoupled together at right angles, one to another, and having a commoncrossover zone at the center thereof with extension arms extendingoutwardly from the common crossover zone. In this embodiment,reinforcing scrim is secured to the surface of each of the segments, thescrim including material arranged generally obliquely to the axis of thesupporting segment, as well as material arranged parallel to the axis ofthe segments. In addition, load lines are provided over the canopystructure, these load lines being disposed along the edges and generallyparallel to the axis of the individual rectangular segments andextending beyond the ends thereof to a common load member. It has beenfound that this structure achieves high stability and high drag with aminimum usage of material and a consequent reduction in weight.

Therefore, it is an object of the present invention to provide animproved aerial decelerator structure having improved strength andstability, improved drag, and reduced weight. 7

It is yet a further object of the present invention to provide animproved aerial decelerator in the form of a cross parachute whichprovides an optimum relationship between the area of material used forshaping the canopy, and the arrangement of reinforcing material forstrengthening the structure while it is functioning as an aerodynamicdecelerator.

Other and further objects of the present invention will become apparentto those skilled in the art upon a study of the following specification,appended claims, and accompanying drawing wherein:

FIG. 1 is an elevational view of the parachute shown in descent, theparachute being constructed in accordance with the principals of thepresent invention; I

FIG. 2 is a plan view of a parachute constructed in accordance with thepresent invention, and showing the load lines broken away adjacent theends of the individual segments; and

FIG. 3 is a detail plan view of a small portion of a rectangular segmentideally suited for use in connection with the parachute structure of thepresent invention.

In accordance with the preferred modification of the present invention,the parachute structure shown in FIG. 1 comprises a canopy portiongenerally designated 10, the canopy including a pair of generallyrectangular flexible segments 11 and 12, these segments having aplurality of shroud or load lines 13-13 depending therefrom. Nonnally,at least sixteen load or shroud lines will be employed, each lineextending entirely over the canopy structure. A load-carrying membersuch as a ring 14 is disposed at the adjoining ends of each of theshroud lines 13-13, this point forming the apex of a solid angle or conewhich includes the canopy structure 10 of the parachute. The structureas shown in FIG. 1 is illustrated carrying a load 15 depending from themember 14 by line 16.

With particular attention being directed to FIG. 2 of the drawing, theindividual rectangular segments 11 and 12 are joined together ata-common crossover zone 18, this zone being generally at the centralportion of each of the rectangular segments 11 and 12. Extension arms19, 20, 21 and 22 extend outwardly from the common crossover zone 18, asis indicated.

Along each of the adjoining lateral edges of the extension arms 19, 20,21 and 22, there is arranged a gore element which is preferably in theform of a quarter circle, these gore elements being identified by thenumeral 23. These gore segments are preferably loosely woven memberssuch as, for example, a loosely woven member of 1,000 denier nylonhaving a center-to-center line spacing of 1 inch. This segment providesenhanced stability for the cross parachute structure.

Referring now to the individual rectangular segments 11 and 12, thesesegments may be fabricated from film material such as, for example,stress-oriented polyethylene terephthalate or the like. As analternative, these individual rectangular segments may be fabricatedfrom woven nylon, of a consistency similar to that utilized inconventional parachute canopies. The nylon material has a built-inpermeability due to its inherent porosity. When utilized at lowaltitudes, it is frequently desirable to fabricate the structure fromnylon since it is normally more readily deployed. When higher altitudesare being considered, such as, for example, altitudes in excess of about300 feet, then, and in that application, polyethylene terephthalatefilms are advantageously employed.

Particular attention is now directed to FIG. 3 of the drawing whereinthe scrim pattern is illustrated, the pattern being shown on a slightlyenlarged scale over that utilized in FIG. 2. This scrim reinforcement issecured to the surface of the rectangular segments, preferably by meansof adhesives or the like, such reinforcing scrim being conventionallyapplied to polyethylene terephthalate films by means of an adhesivefilm. In this connection, a first plurality of reinforcing scrim isarranged generally obliquely to the axis of the rectangular segment,these scrim lines being shown as at 25. A second plurality ofreinforcing scrim is applied to the rectangular segment in a directiongenerally parallel to the axis of the individual segment. This scrimpattern is shown in FIG. 3 as at 26. A further plurality of reinforcinglines is shown in FIG. 3 at 27, the lines 27 forming the dual functionof reinforcing lines and shroud lines. In the segment shown in FIG. 3,five individual shroud lines are shown being secured to the surface ofthe rectangular segment, this being in contrast to the four individuallines shown in F108. 1 and 2. Generally speaking, inparachutes made inaccordance with the present invention, a minimum of four shroud lineswill be employed for purposes of stability. It will be apparent that thelines 27 of FIG. 3 correspond generally to the lines 13 of theembodiment shown in FIG. 1.

The individual rectangular segments are formed so as to have a length towidth ratio of about 3. ln one typical embodiment, a parachute capableof use with payloads of about pounds will utilize rectangular segmentshaving lengths of 20.6 feet, and widths of 6.33 feet. Larger structureswill be employed for larger payloads, or for payloads capable of morerapid descent rates. In this typical structure, the oblique scrim shownat in FIG. 3 will preferably be nylon of 440 denier placed at 1-inchcenters. The longitudinal material shown at 26 will preferably be 1,000denier placed on 1-inch centers. The load or shroud lines 27 will alsopreferably be bundles of five 1,000 denier yarns placed at equalintervals across the width of the member.

In such a typical structure, performance characteristics as compared toa circular flat parachute are shown in table 1 below.

TABLE l.-PARACHUTE PERFORMANCE Down time It will be seen that the dragcoefficient for the cross parachute is substantially equal to the dragcoefficient of the circular flat parachute, and that the stability isfar greater. The stability is given in degrees of rocking experienced bythe parachute during descent. Also, it will be observed that the descenttime is substantially equal for the two parachute structures.

As aids in deployment, inflatable toroidal members may be utilized aboutthe periphery of the structure, if desired, however experience hasdetermined that these aids are not nor mally required, since thestructure deploys readily and rapidly.

It will be appreciated that the parachute structure of the presentinvention may be employed for use with a variety of payloads, includingpersonnel, if desired. The structure is rugged, dependable, and highlystable during deceleration descents.

What we claim is:

1. Cross parachute means comprising:

a. a pair of generally rectangular flexible segments of a certainlimited porosity, each segment having an elongated axis, the segmentsbeing disposed at right angles one to another and having a commoncrossover zone generally at the central portions thereof, and extensionarms extending outwardly from said common crossover zone;

b. a first plurality of reinforcing scrim secured to the surfaces ofsaid segments with the scrim axes extending generally obliquely to theaxis of its supporting segment;

c. a second plurality of reinforcing scrim secured to the surfaces ofsaid segments with the scrim axes extending generally parallel to theaxis of its supporting segment;

(1. a third plurality of reinforcing scrim secured to the surfaces ofsaid segments with the scrim axes extending generally parallel to theaxis of its supporting segment and extending beyond the ends of thesegment and being secured to a common load member so as to form shroudlines for said parachute, the lines being secured to the supportingsegment generally along the lateral edges thereof and at substantiallyequally spaced lateral intervals across the width of the supportingsegment; and

e. a gore fabricated from a material having a porosity substantiallygreater than that of said rectangular segments being disposed along andsecured to adjacent lateral ed es of each pair of mutuall adjacentextension arms, sal gore extending substantra ly the entire extent ofeach of said extension arms.

2. The cross parachute means as defined in claim 1, being particularlycharacterized in that said rectangular segments are nonporous flexiblefilm members.

3. The cross parachute means as defined in claim 1 being particularlycharacterized in that said second plurality of reinforcing scrim isdisposed at frequent intervals across said segments, and wherein saidthird plurality of reinforcing scrim members consists of at least foursubstantially equally spaced lines.

4. The cross parachute means as defined in claim 1 being particularlycharacterized in that the dimensional length to width ratio of theindividual rectangular segments is substantially 3.

1. Cross parachute means comprising: a. a pair of generally rectangularflexible segments of a certain limited porosity, each segment having anelongated axis, the segments being disposed at right angles one toanother and having a common crossover zone generally at the centralportions thereof, and extension arms extending outwardly from saidcommon crossover zone; b. a first plurality of reinforcing scrim securedto the surfaces of said segments with the scrim axes extending generallyobliquely to the axis of its supporting segment; c. a second pluralityof reinforcing scrim secured to the surfaces of said segments with thescrim axes extending generally parallel to the axis of its supportingsegment; d. a third plurality of reinforcing scrim secured to thesurfaces of said segments with the scrim axes extending generallyparallel to the axis of its supporting segment and extending beyond theends of the segment and being secured to a common load member so as toform shroud lines for said parachute, the lines being secured to thesupporting segment generally along the lateral edges thereof and atsubstantially equally spaced lateral intervals across the width of thesupporting segment; and e. a gore fabricated from a material having aporosity substantially greater than that of said rectangular segmentsbeing disposed along and secured to adjacent lateral edges of each pairof mutually adjacent extension arms, said gore extending substantiallythe entire extent of each of said extension arms.
 2. The cross parachutemeans as defined in claim 1, being particularly characterized in thatsaid rectangular segments are nonporous flexible film members.
 3. Thecross parachute means as defined in claim 1 being particularlycharacterized in that said second plurality of reinforcing scrim isdisposed at frequent intervals across said segments, and wherein saidthird plurality of reinforcing scrim members consists of at least foursubstantially equally spaced lines.
 4. The cross parachute means asdefined in claim 1 being particularly characterized in that thedimensional length to width ratio of the individual rectangular segmentsis substantially 3.